How do you verify a SPNEGO token once it's generated in integration testing

Question

I have used the library SimpleKdcServer and created an intergation test which at the end produces a SPNEGO token. Is there a way to verify it, like can I somehow reverse the process and make sure that the genreated token is the correct value or format?

For now I have a check to verify it starts with "Negotiate" but is that enough, is there not a more robust way to do it like:

asserThat("Negotiate XfkeEmf34FNDM...").isEqualTo(someMethodToReverseToken())